Simplify the following expression: $k = \dfrac{4y - 5}{2y + 1} - \dfrac{6x}{2y + 1}$ You can assume $x,y,z \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{4y - 5 - (6x)}{2y + 1}$ $k = \dfrac{4y - 5 - 6x}{2y + 1}$